Studies underway continue earlier observations on immune complex biology using site-specifically cross-linked model complexes. Two major aspects are under study at the moment. First, the hepatic handling of model complexes in auto-immune mice is being studied in detail using organ perfusion. This approach allows a more detailed and subtle understanding than whole animal studies. Autoimmune mice show and abnormality in handling complexes before they are clinically ill. Second, in studies just underway, the influence of drugs which are known to ameliorate auto-immune disease upon immune complex handling in normal and auto-immune mice, is being explored.